The present invention relates to machines used in the manufacture of cigarettes, and more particularly to mass-flow elevators for transporting the output of cigarette makers to cigarette packing machines.
In a typical filter tipping machine, two-up tobacco rods are transferred along a series of drums for the execution of manufacturing steps which ultimately create, near the exit of the tipping machine, a succession of individual, filter tipped cigarettes that are discharged from a final, exit drum. Usually a stack-former apparatus is placed adjacent the exit drum of the tipping machine to initiate the formation of a moving, multi-layered mass of cigarettes. The stacked mass of cigarettes is then directed through a mass-flow elevator to the accumulator and/or a tray filler, which interfaces with a cigarette packer. Downstream of the stack-former, tracking of individual cigarettes is usually not possible.
Mass flow elevators of the prior art commonly comprise a pair of mutually opposing, vertically oriented endless belts which vertically transport the stacked (multi-layered) mass of cigarettes to a height that is conducive to feeding cigarettes to the packer and/or an accumulator or tray filler. It has been found that when one of the belts fall, the elevator may still continue to vertically transport cigarettes, but in a manner that increases the risk of skewed cigarettes, product degradation (e.g., flatten xe2x80x9cDxe2x80x9d shaped cigarettes) and machine jams downstream of the elevator.
Tipping machines of the prior art have included one or more quality inspection stations at a location along the cigarette stream when the individual cigarettes have been fully formed and separated from one another. Typically, these devices inspect the cigarettes for loose ends, proper rod density, missing filters and other quality-indicative features. Because cigarettes are not fully constructed until close to the exit station of the tipping machine, there is but little room and opportunity for the placement and operation of the inspection devices and for effecting rejection of unacceptable cigarettes (i.e., cigarettes which have failed to pass one or more of the aforementioned quality inspection tests). There is also little or no room nor time for confirmation of a detector""s initial reading.
Because cigarettes were heretofore mixed amongst each other soon after the exit of the tipping machine, all rejections of unacceptable cigarettes had been effected within the tipping machine, typically at a single rejection station at a fixed location along a single drum (usually the exit drum or a dedicated rejection drum just upstream of the exit drum). At the rejection station, a blast of compressed gas would be communicated to an underside of a passing flute known to carry an unacceptable cigarette by the flute tracking system of tipping machine controller. The blast is gauged to be sufficient to overcome the vacuum retention system of drum so as to blow the cigarette off the respective drum flute. Because the blast has to be complete and so immediate in so little space and time, the ejection process often rips or otherwise further damages the rejected cigarettes. The additional damage also tends to mask the true condition of the cigarette as it appeared at the inspection station, hampering resolution and correction of the casual problem at the cigarette maker.
Also, prior ejection systems heightened the risk of jams, because all ejections, for whatever reason out of a multiple of reasons, had to be undertaken at the exit station amongst a host of high speed, complicated rotating machinery. Additionally, if a consecutive series of cigarettes failed inspection, the repetitious operation of the rejection system would degrade its performance and/or tend to interfere with the vacuum retention system of the machine.
Heretofore, sampling of good cigarettes included the practice of a machine operator manually scooping a sample of cigarettes from the stacked mass. The scooping action has been found to occasionally skew cigarettes along the stack and to sometimes damage product.
Accordingly, an object of the present invention is to provide a cigarette elevator arrangement for transferring the output of a cigarette making module without the aforementioned problems of the prior art.
It is another object of the present invention to provide such a cigarette elevator, which has the additional capacity to reject cigarettes outside of the tipping machine so as promote a more efficient and reliable cigarette ejection system.
It is yet another object of the present invention to provide a cigarette elevator having the capacity to preserve order amongst a procession of cigarettes beyond a cigarette maker and/or its tipping machine so as to facilitate further and/or confirmatory inspection of the cigarettes.
It is another object of the present invention to provide a cigarette elevator module which facilitates additional inspection of the cigarettes without imposing significant changes to the layout of the cigarette manufacturing module.
It is yet another object of the present invention to provide a cigarette elevator such that repetitive rejection of cigarettes can be undertaken without disruption of acceptable cigarettes and with less risk of causing machine jams.
Still another object of the present invention is to provide an arrangement for confirmatory inspection of finished cigarettes such that false rejection of acceptable cigarettes is minimized.
Another object of the present invention is to provide a drum elevator having provision for gentle, damage-free sampling of cigarettes at the moment of their production.
Yet another object of the present invention is to gently transport the output of a cigarette maker to a cigarette packer and/or accumulator such that deformation of good cigarettes is minimized and the rejection of unacceptable cigarettes is as complete and accurate as possible.
These and other objects are achieved with the present invention which provides a drum elevator and method of elevating cigarettes, wherein the apparatus comprises a series of rotatable cigarette transferring drums that includes a first plurality of horizontally disposed drums at a first elevation and a second plurality of vertically disposed drums extending to a second, desired elevation. The second plurality of vertically disposed drums receive the output of the first plurality of drums, and the first and second pluralities of drums being adapted to receive a procession of cigarettes at the first elevation and to elevate the cigarettes to the second elevation while maintaining the cigarettes arranged in the procession. The drum elevator further comprises a rejection station at a location along the transfer path; a controller operative to selectively actuate the rejection station; and a stack former at the second elevation which receives the output of the second plurality of vertically disposed drums.
Another aspect of the present invention includes provision of a soft ejection station comprising a nip defined between a pair of adjacent cigarette conveying drums, with the upstream drum including a second vacuum plenum at the nip between the drums and an arrangement for selectively evacuating and venting the second plenum. Accordingly, the second vacuum plenum is arranged both to draw cigarettes onto the upstream drum upon evacuation and to gently release cigarettes from between the drums upon venting. Such action avoids damaging the sampled cigarettes during the ejection process so that they may be reclaimed, and it is not intrusive upon adjacent portions of the cigarette procession.
Yet another aspect of the present invention includes provision of a stack former comprising a counter arranged to generate a signal indicative of a rate of cigarettes entering the stack former, a substantially stationary element at a location along a pathway of the cigarettes such that cigarettes are discharged beyond the element as a stacked mass; and a conveyor controller configured to adjust an adjustable conveyor drive mechanism responsively to the signal indicative of cigarette rate so that the stacked mass of cigarettes is maintainable at a predetermined height.